Summary: This project is for all VRC clinical trials related to preventive HIV vaccines. These currently consist of a screening protocol and several Phase I clinical trials including: a study of a 4-plasmid DNA vaccine, a study of a 6-plasmid DNA vaccine, a study of a recombinant adenoviral vector (rAd) vaccine, and three studies to evaluate DNA vaccines and rAd vaccine combined in a prime-boost regimen.